In recent years, a non-thermal method, employing a photocurable resin, for immobilizing an enzyme or bacterial cells has become known as an advantageous method in waste-water treatment and diagnosing drugs. Among such photosensitive resins, PVA-SbQ resin is employed in some applications (Japanese Patent Publication (kokoku) No. 8-23545 and Japanese Patent Application Laid-Open (kokai) No. 2-240555).
PVA-SbQ resin is applicable to a variety of uses by virtue of high stability and safety. However, since PVA-SbQ resin has a cationic moiety in the molecule, only limited quantities of these compounds can be dissolvable or miscible in immobilization of an enzyme or bacterial cells, which is problematic.
PVA-SbQ resin has another drawback. When the PVA-SbQ is in a poorly dried state and contains a large amount of water, its photosensitivity decreases considerably. Thus, when a compound that cannot be subjected to a drying step is immobilized under hydrous conditions, hardenability of the resin is insufficient.
The present inventors previously developed a photopolymerizable saponified poly(vinyl acetate)-based photosensitive resin having a specific structure as a material which exhibits excellent storage stability, affinity, miscibility, or solubility with respect to a variety of compounds. This is described in Japanese Patent Application Laid-Open (kokai) No. 2000-181062.
The photosensitive resin and the composition thereof disclosed in Japanese Patent Application Laid-Open (kokai) No. 2000-181062 are excellent as a photoresist. In this application, an aqueous solution is applied to a substrate, dried, patternwise exposed, and developed. However, the phototosensitivity of the materials is insufficient for use as a photosensitive gel-forming agent that forms gel through photocuring under water-rich conditions. Thus, a photosensitive resin and a photosensitive resin composition exhibiting higher sensitivity have been desired.
In addition to Japanese Patent Application Laid-Open (kokai) No. 2000-181062, WO97/33202 discloses some similar polymerizable photosensitive resins formed of saponified poly(vinyl acetate) having a vinylic unsaturated bond-containing fragment as a pendant group for use as a photoresist for forming a pattern. However, the above disclosed photosensitive resins also exhibit poor photosensitivity.
(Meth)acrylic acid derivatives having in the molecules thereof a moiety which is similar to a pendant molecular chain included in the saponified poly(vinyl acetate) disclosed above are reported in Japanese Patent Application Laid-Open (kokai) Nos. 2001-58972 and 11-327139. However, these documents do not disclose that the (meth)acrylic derivatives can be used in aqueous or water-containing compositions, and water-solubility of the derivatives is not confirmed in the descriptions.